Dengue fever is a viral (flavivrus) disease transmitted by Aedes albopictus and female A. aegypti mosquitoes. It is estimated that 50 to 100 million people in more than 100 countries are infected each year with dengue viruses.

There are four different types of dengue virus, and there is no cross-immunity, so a person may be stricken with dengue fever four times in his life. The most active feeding times for dengue vector mosquitoes is for a few hours after daybreak and in the afternoon for a few hours just after dark (dusk).

As opposed to the night-feeding mosquitoes that transmit malaria, these species tend to be “urban,” may also feed during daylight hours (also indoors, in the shade, and during overcast weather), and are known to bite below the waist. Dengue fever is seen chiefly in the Caribbean and South America, as well as other tropical and semitropical areas, such as Southeast Asia, Africa, and Mexico. In the United States, cases have been noted in Texas, Hawaii and Florida. The larvae flourish in artificial water containers (e.g., vases, tires), often in a domestic environment.

The incubation period following a mosquito bite is two to eight days. The disease is self-limited (five to seven days) and characterized in older children and adults by a sudden onset of symptoms, including: Read more »

An all-natural insect repellant called nootkatone found in Alaska yellow cedar trees and citrus fruits (like grapefruit) is being developed by the CDC. It is so safe for humans, it is even an FDA-approved food additive.

Nootkatone is not only safe for humans and the environment, it is a highly effective insect repellant. In fact, it is not only a bug repellant, but an insecticide causing death to biting insects like mosquitoes within 15 seconds.

Application of 2% nootkatone will also control ticks for up to 42 days at greater than 97 percent efficacy.

It is non-greasy, dries very quickly, and it has a very pleasant, citrus-y grapefruit odor to it.

Sounds too good to be true… But it is true! The only downside right now is that it is not available in the market, mainly because it is expensive — $4,000 per kilogram for highly purified food-grade material, which is used in parts-per-million amounts as a flavoring agent.

However, there are two companies that are currently working to make it available as insect control, hopefully in the near future!

In the June 11, 2009 issue of the New England Journal of Medicine appears an article by Mark Duffy and colleagues entitled “Zika Virus Outbreak on Yap Island, Federated States of Micronesia.” This outbreak occurred in 2007, and was described as a cluster of 108 persons with confirmed or suspected infection, characterized with main symptoms of skin rash, fever, conjunctivitis, and painful joints. Other less common symptoms were muscle aches, pain behind the eyes, tissue swelling and vomiting.

As reported by the authors, there were no hospitalizations, bleeding problems in victims, or deaths. The predominant mosquito culprit was Aedes hensilli. The disease was determined to be mild in this outbreak. Zika virus is in the family of flaviviruses, which include West Nile, dengue, and yellow fever viruses. It has been diagnosed in Asia and Africa, and is transmitted by infected mosquitoes. Before this particular outbreak, there had only been 14 cases of human Zika virus disease previously documented.

The diagnosis was made in this outbreak by sending serum samples from patients to the Centers for Disease Control and Prevention (CDC) Arbovirus Diagnostic and Reference Laboratory in Fort Collins, Colorado.

How did this virus turn up in Yap? The most likely introducer was an infected mosquito or human. So, given the abundance of mosquitoes and propensity of people to travel, we may soon see this disease in other regions around the globe.

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